Statalist


[Date Prev][Date Next][Thread Prev][Thread Next][Date index][Thread index]

Re: st: Problem with xtmixed


From   "rgutierrez@stata.com" <rgutierrez@stata.com>
To   "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu>
Subject   Re: st: Problem with xtmixed
Date   Wed, 4 Jun 2008 09:15:35 -0700

Noori Akhtar-Danesh <nakhtardanesh@cogeco.ca> is having difficulty getting
-xtmixed- to match -xtreg- and -gllamm-.  When running -xtmixed-, Noori
types the following:

   . xtmixed  birwt male ... pretri2 pretri3 || momid, mle

and the resulting estimation is having difficulty converging.  Noori has
simply omitted the colon after the group identifier -momid-, causing
-xtmixed- to interpret the above as

   . xtmixed  birwt male ... pretri2 pretri3 || _all: momid, mle

an entirely different (and somewhat nonsensical in this case) model, hence
the failure to converge.

Typing

   . xtmixed  birwt male ... pretri2 pretri3 || momid:, mle

(with the colon after -momid-) will achieve the desired result.

Noori is not the first to be bit by this insidious bit of syntax.  The
original intent of providing a shortcut has proven in this case to not to be
worth the confusion it may cause.  As such, a future version of -xtmixed-
will require explicit specification of the level group identifier with the
colon, and issue a syntax error otherwise.

--Bobby
rgutierrez@stata.com
*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/

Privileged, confidential or patient identifiable information may be contained in this message. This information is meant only for the use of the intended recipients. If you are not the intended recipient, or if the message has been addressed to you in error, do not read, disclose, reproduce, distribute, disseminate or otherwise use this transmission. Instead, please notify the sender by reply e-mail, and then destroy all copies of the message and any attachments.

*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/



© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index